Step 1: Analyze each neurotransmitter.
- P. Acetylcholine – (iii) Attention and memory: Critical for learning and memory processes.
- Q. Dopamine – (i) Movement and pleasure sensation: Regulates motor control and reward pathways.
- R. Serotonin – (ii) Sleep, anxiety, and appetite: Influences mood, sleep cycles, and appetite regulation.
- S. Norepinephrine – (iv) Arousal and mood: Affects alertness and emotional arousal.
Thus, the correct matching is: \[ \boxed{{P–iii; Q–i; R–ii; S–iv}} \]